The present invention relates to a keyswitch, especially to a keyswitch assembled from top direction to simply process and prevent lateral shake.
FIG. 1 shows a conventional computer keyswitch, which is a lever type keyswitch and comprises a keytop 10a, a resilient dome 11a, a first lever 12a, a second lever 13a and a base 14a. The first lever 12a and the second lever 13a are in scissors arrangement. The first lever 12a has a pivotal shaft 15a on bottom thereof and the second lever 13a has a pivotal shaft 16a on bottom thereof, the pivotal shafts 15a and 16a are pivotally arranged into pivotal stages 17a and 18a on top of the base 14a. The top end of the first lever 12a and the second lever 13a are pivotally arranged into bottom of the keytop 10a, whereby the first lever 12a and the second lever 13a forms a link mechanism. The resilient dome 11a is placed within the moving stroke of the keytop 10a. When the keytop 10a is pressed downward or lifted upward; and guided by the first lever 12a and the second lever 13a, the resilient dome 11a below the keytop 10a can switch on and off the membrane circuit 19a. 
However, in above-mentioned keyswitch with a first lever 12a and a second lever 13a in scissors arrangement, the first lever 12a and the second lever 13a should be assembled along a specific inclined angle. The assembling thereof is cumbersome, and hard to automatic.
Moreover, in above-mentioned keyswitch, the pivotal shafts 15a and 16a of the first lever 12a and the second lever 13a are pivotally arranged into pivotal stages 17a and 18a on top of the base 14a. The first lever 12a and the second lever 13a cannot be firmly retained by the base 14a. The keytop 10a is shaken during key pressing operation.
Moreover, in above-mentioned keyswitch, the pivotal stages 17a and 18a of the base 14a have the problem of material congestion when being bent. The pivotal shafts 15a and 16a of the first lever 12a and the second lever 13a cannot be tightly fit into the pivotal stages 17a and 18a on top of the base 14a. The first lever 12a and the second lever 13a cannot be firmly retained by the base 14a. 
It is an object of the present invention to provide a keyswitch wherein the first lever thereof can be vertically assembled to the second lever thereof. The assembling of the lever mechanism in the present invention does need specific inclined angle and cumbersome process.
It is another object of the present invention to provide a keyswitch when the two lower pivotal shafts of the second lever thereof are pivotally arranged in the second pivotal stages, the two clamping parts below the second lever clamp the second pivotal stages, respectively. Therefore, the first lever and the second lever are firmly retained on the base and stably guide the keytop such that the keytop will not be shaken during operation.
It is another object of the present invention to provide a keyswitch wherein the first pivotal stage thereof has two broken edges on two lateral bending sides thereof, the first pivotal stage will not have the problem of material congestion during manufacture. The lower pivotal shaft on bottom of the first lever is precisely arranged in the first pivotal stage. Therefore, the first lever and the second lever are firmly retained on the base and stably guide the keytop.
To achieve above object, the present invention provides a keyswitch comprising a keytop, a resilient dome, a first lever, a second lever and a base with pivotal stages. The first lever has two convex parts on centers of two lateral sides thereof and the second lever has two concave parts on centers of two lateral sides thereof and corresponding to the two convex parts. The convex part has an opened groove and the concave part has a pivotal rod corresponding to the opened groove and pivotally arranged into the opened groove. Therefore, the first lever can be vertically assembled to the second lever. The second lever has two clamping parts on two lateral sides thereof and clamping the pivotal stages of the base. Therefore, the first lever and the second lever are firmly retained on the base and stably guide the keytop such that the keytop will not be shaken during operation.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which: